XXXXY syndrome
| XXXXY syndrome | |
|---|---|
| Other names | Fraccaro syndrome 49,XXXXY syndrome |
| A 19-year-old boy with XXXXY syndrome and prognathism | |
| Specialty | Medical genetics |
| Usual onset | Prenatal |
| Duration | Lifelong |
| Causes | Cellular nondisjunction during meiosis |
| Diagnostic method | Karyotype |
| Frequency | 1 in 85,000 to 100,000 |
XXXXY syndrome, also known as 49,XXXXY syndrome or Fraccaro syndrome, is an extremely rare aneuploidic sex chromosomal abnormality. It occurs in approximately 1 out of 85,000 to 100,000 males. This syndrome is the result of maternal non-disjunction during both meiosis I and II. It was first diagnosed in 1960 and was coined Fraccaro syndrome after the researcher.